Question

Which of the following amino acids are essential amino acids in humans:
A. Leucine
B. Lysine
C. Isoleucine
D. Serine
Choose the correct answer from the options given below:

• A. A, B, and C Only
• B. B, C, and D Only
• C. A, B, C and D
• D. A, C, and D Only

Hint:

A useful mnemonic to remember the nine essential amino acids is "PVT TIM HALL": Phenylalanine, Valine, Threonine, Tryptophan, Isoleucine, Methionine, Histidine, Arginine (conditionally essential), Leucine, Lysine.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Essential amino acids are those that the human body cannot synthesize on its own in sufficient quantities. Therefore, they must be obtained from the diet. Non-essential amino acids can be synthesized by the body.
Step 2: Detailed Explanation:
There are nine essential amino acids for adult humans: Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, and Valine.
Let's classify the amino acids given in the question:


A. Leucine: This is an essential amino acid.

B. Lysine: This is an essential amino acid.

C. Isoleucine: This is an essential amino acid.

D. Serine: This is a non-essential amino acid, as it can be synthesized in the body from other molecules, such as glycine or 3-phosphoglycerate.

Step 3: Final Answer:
Leucine, Lysine, and Isoleucine (A, B, and C) are essential amino acids, while Serine is not. Therefore, the correct option includes A, B, and C only.